Treatment of phosphates.



El Cl mumcrn or PHOSPHATES. APPLICATION FILED DEC. I9. I913.

Patented Oct. 15, 1918.

3 SHEETS-SHEET E. C. SOPER. TREATMENT or ruosrnnes E. C. SOPER. TREATMENT OF PHOSPHATES.

APPLICATION FILED DEC. 19. I913.

Patented Oct. 15, 1918.

3 SHEETS-SHEET Illltb 01 1,-

UNITED STATES PATENT OFFICE.

ELLIS C. SOPER, 0F CHATTANOOGA, TENNESSEE, ASSIGNOR TO ARMOUR FERTILIZER WORKS, OF CHICAGO, ILLINOIS, A CORPORATION OF NEWJEBSEY.

TREATMENT OF PHOSPHATES.

Specification of Letters Patent.

Application filed December 19, 1813. Serial No. 807,598.

To all whom it may concern:

Be it known that I, ELLIS C. Sornma citizen of the United States, residing at Chatta nooga, in the county of Hamilton and State of Tennessee, have invented certain new and useful Improvements in the Treatment of Phosphates, of which the following is a speci cation.

My invention relates to new and useful improvements in the treatment of phosphates, and particularly relates to the conversion of insoluble calcium phosphate into citrate soluble form for use as fertilizers. It has been proposed to treat insoluble calcium phosphate, with the addition of alkali metal salts and other reagents or alkalis, with heat at a calcining temperature in order to convert the same into citrate soluble form, but such proposals have been proven, as far as I am aware, commercially impracticable because of the fact that it has been necessary to treat batches of the raw material intermittently, and in such small quantity as to make the cost of production preclude the use of the process commercially. It is, therefore. my purpose to provide a method of procedure. which will provide for the continuous treatment of insoluble calcium phosphate, with added alkali metal salt or salts or other reagents or alkalis, to render the same citrate soluble, so that the soluble form may be produced in suflicient quantity, and at cost low enough to admit of the practised commercially.

It has been demonstrated that, in order to produce complete conversion of the insoluble calcium phosphate with added alkali metal salt, to citrate soluble form, it is essential that the mixture be initially rendered porous so that the heating gases employed in the calcination may find ready access throughout the body of the material being treated, and any gases formed as the result process being of chemical reactions may escape from the body of the material, in order that the percentage of conversion from insoluble to citrate soluble form will be practicable.

In order to accomplish the above objects, I preferably rovide a structure to be hereinafter described which, in one of its forms, may be used for rendering the raw material porous, as above set forth, after which it may be conveyed to a suitable calcining furnace. for instance, a rotary kiln. to subject it to calcination and consequent conversion to soluble form, or the invention may take a form in which it is useful not only for performing the function of rendering the mate rial porous, but also of calcinin. In the latter-mentioned form there is su stantially no difference in structure over the form first mentioned except that the dimensions are greater in order that the period durin which the material is subjected to heat Wil be lengthened.

The invention consists in the improve-- ments to be more fully described hereinafter, and the novelty of which will be particularly pointed out and distinctly claimed.

I have fully and clearly illustrated one form of apparatus adapted tocarry out my invention in the accompanying drawings, to be taken as a part of this specification, and wherein:

Figure 1 is a vertical lon itudinal section through a structure embod ying m invention, the section being taken on the inc 1]. of Fig. 2;

Fig. 2 is a vertical transverse section of the embodiment shown in Fig. 1, taken on the line 22 of Fig. 1;

Fig. 3 is an enlarged vertical section taken on the line 33 of Fig. 1;

Fig, 4 is a detailed plan view, partly in section, of a portion of the carrying table;

Fig. 5 is a section on the line 5-5 of Fig. 4;

Fig. 6 is a plan view showing another form of the table;

Fig. 7 is a section on the line 77 of Fig. 6;

Fig. 8 is an end elevation of another form of the table;

Fig. 9 is a detailed plan view of a portion of the table and constructed as shown in Fig. 8;

Fig. 10 is an end elevation of still another form of the table; and,

Fig. 11 is a detailed plan view of the construction shown in Fig. 10. k

Referring to the drawings by characters of reference:

A desi nates generally a furnace chamber formed by a suitable inclosing structure which may be constructed of "ertical side walls 1. 1, front and rear end Walls 2, 3, respectively. and a crown or roof 4. It will be understood that the structure may be of proper material to resist high temperatures or lined with such material. The side walls .2. Through the said ma rest on suitable foundation walls 5 which, in fact, form part of the bases of the side walls, as shown in Fig. 2. The side walls may also be extended vertically above the lower side edges of the crown to form a receptacle for an earth fill 6 for heat insulating purposes, so that the heat will not be lost by radiation. 7

The foundation walls 5, above mentioned, project inward from the main side walls 1, 1. to form ledges 7 running from front to rear of the chamber A, and upon which are supported track rails 8 of any suitable form for a purpose to bepresently set forth.

The front end wall 2 is constructed with an opening 9, and the rear wall 3 has an outlet opening 10. to which leads an inclined wall or chute 11 formed on the rear face of a bridge wall 12, extending transversely of the chamber A. at the rear of the latter in advance of said rear wall 3.

In the rear wall 3, at a point adjacent the upper portion thereof, is an inlet nozzle 13 for a blast pipe for admitting a combustion medium to be burned in the furnace, such, for instance, as a mixture of air and producer gas, natural gas, oil or pulverized coal. I might also use waste heat from a calcining furnace or heat from another source in heating the furnace when it ts used only as a drier. This blast nozzle s arranged preferably. to direct its blast i101!- zontally and lengthwise of the furnace chamber for a purpose to be presently described. At its forward end the furnace chamber is provided with an outlet stack 14, which may be controlled by a suitable damper 15, said stack preferably rising from and opening through the crown or roof of the chamber.

In one of the side walls 1, adjacent the forward upper portion thereof. as shown in Fig. 1, is an outlet 16 which is connected by a flue or duct 17 with an inlet 1% located in the forward lower portion of the said side wall, said fine or duct being located outside of the furnace, as shown clearly in Fig.

side wall 1. at the bottom thereof, and preferably just in advance of the bridge wall 12, is an outlet 19 leading to a stack 20. The line 17 is preferably provided with a damper 21, of any suitable construction, whereby communication with the furnace chamber may be established and cut oil'.

Arranged within the furnace chamber is an emlies: table adapted to receive, on the upper surface of the upper run thereof, the material to be treated. This table may take a number of different forms without departing from my invention, but I prefer to construct it as follows:

21, 21, designate vertical side frames, each of which provided at its lower portion with flanged running wheels 22 adapted to travel on the track-rails 8, 8, heretofore described. These side frames 21, 21, are con nected rigidly by means of cross-bars 23 (see Fig. 3). The side frames are each provided with upper and lower rails 24, 25, respectively, upon which run flanged uidewheels 26 upon the ends of cross-sha is or bars 27, which serve as connecting means for the parts forming the endless table to be presently described. The preferred form of this table comprises a plurality of parts which are flexibly connected by said shafts 27, and each of which comprises a plate 28 extending transversely of the table, and provided on its transverse longitudinal edges with flanges 29 inclined toward each other, as shown in Figs. 5 and 7, said plates being preferably curved in cross section, as shown in Figsnfi and 7 of the drawings, although they may be flat, as shown in Figs. 8 and 10, if desired. These transverse members or plates 28 are mounted upon su porting and connecting members 30 provi ed with hinge ears 31, by means of which they are pivotally or hingedly connected to the transverse bars or shafts 27. hretofore described. The transverse plates or members 28 serve as supporting and holding means for suitable refractory material to serve as the supporting surface of the table, and to heat the material being treated. Preferably the flanges 29 are inclined inwardly to cooperate with blocks 32 of refractory material located along the longitudinal edge portions of said plates, which blocks are formed at the bases of their outer sides with shoulders 33 to lock under said flanges. The blocks 32 are preferably of such material as to resist high temperatures, and be a poor conductor. The said blocks, on their inner faces, are provided with inclined faces 34 which, when the blocks are in position on the supporting plate. form a wedge-shaped space between the blocks ada )ted to receive a? wedgeshaped key-bloclr 35 which not only serves to complete the supporting surface, but serves as a key in cooperation with said blocks 32 and the flanges 29 to lock'all of said blocks in position. By this arrangement the blocks may be easily removed and replaced when necessary.

The above description applies to the construction shown in Figs. 4 and and the construction shown at the right of Figs. 6 and 7, but I desire it understood that my invention is not limited to any particular way of securing the blocks in place. as I may use the construction shown at the left of Fig. 7, in which the flanges 29 are employed, but. blocks 36 with straight inner sides are employed instead of having the inclincd faces as above described. said blocks being provided with adjacent grooves 37 adapted to receive cement or other keying or interlocking material.

' guide-ways Inthe construction shown in Figs. 8 and 9, instead of employing plateswhich are continuous across the table, I may form each section of the table of a plurality of plates 38 arranged end to end, and each formed with hinged ear 39, adapted to hlngedly receive the transverse shaft 27, heretofore described. In the form shown in Figs. 8 an 9 the front and rear edges of each of these plates are provided wit inwardly-directed flanges 27 forming a wedge-shaped space adapted to receive the correspondingly formed base 40 of a block 41 of refractory material, said blocks being inserted in place by sliding the said bases 40 beneath the said flanges by movement transversely of the plate. In Fig. 10, instead of having the front, and rear inclined flanges, I provide a wedgeshaped boss 42 in the center of the plate adapted to interlock with an undercut recess 43 in the base of the block, the latter being secured in place by sliding it into engagement with the boss by movement transversely of the plate. These plates, whether of the form shown in Figs. 4 to 7, or of the forms shown in Figs. 8 to 11, are flexibly connected by the said transverse bars or shafts 27, and form an endless table adapted to move lengthwise of the main frame, the said flanged running-wheels 26 traveling on the upper and lower rails 24, 25, heretofore described. At the ends the sectional table passes around suitable sprocket wheels 44, 44", having teeth or projections 45 and intervening spaces 46. the latter being adapted to receive the wheels 26 on the transverse shafts or bars 227 during movement of the table. The sprocket wheel 44 at the rear end of the table is mounted on a shaft 47 journaled in fixed bearings 48, but I prefer to mount the sprocket-wheel 44 at the forward end of. the table on a shaft 47 journaled in bearing boxes 49 mounted in horizontally-disposed 50 in the side frames 21, and adapted to be adjusted in side guide-ways to regulate the tension on the endless table. On one end of the forward sprocket-wheel shaft 47 is a worm-whee1 51 meshing with a worm-pinion 52 mounted'on a suitable drive shaft 53, by means of which the table is caused to travel in the direction of the arrow, as shown in Fig. 1, by power from any suitable source. The flexible table is preferably of such length that, when in position in the furnace chamber A, the inner end thereof will take a position over the chute 11 to discharge material carried on the table upon said chute. while the forward end of the table projects outside of the furnace through the opening 9. It will be seen that the whole table may be easily withdrawn from the furnace chaniber for inspection or repair.

Arranged outside the furnace and over in Fig. 1.

is a protective hood 56, covering the said front end and constructed to confine the heat and prevent cooling of the table and escape of heat from the furnace, said hood being preferably lined with, heat-resisting material, such as asbestos. The hood is preferably mounted on flanged wheels 57 running on the rails 8, so that the hood may be conveniently moved toand, withdrawn from o eratlve posltion. Thehood carries a suite. le scraper 58 adapted to clean the table of any material whic maynot be discharged therefrom at the chute 11. This scraper is preferably adjustable toward and away fromthe carrying surface of the table by means of a rack The track rails 8 are preferably arranged at a height above the inlet 18 and theexit 19, and the upper surface of the table trav els at a point beneath the blast nozzle 13 and the outlet 16.

I may provide openings 6() in the side walls of the furnace to permit inspection of the interior thereof, ing of the metal parts ofthe table, should they become too hot. be covered with suitable closures 61, which may be opened when it is desired to inspect the interior of the furnace, or to admit the The furnace may also cooling air thereto. be provided, in the front Wall, with an inand with a similar spection opening 62,

opening 63 in therear wall through which the conditionslin, the furnace maybe inspected during the operation of dryingand calcining. f

It wil be understood that the blocks of refractory material constituting the table are arranged close together when in horizontal or carrying position, so that the liquid or plastic mass will not flow down through the conveyor without being heated, but when the blocks reach the dischar e end of the table the separation of the locks, owing to the turning of the same over the end sprocket. 4ft, will serve to se arate the material from the surface of'sald blocks, which material will be discharged upon the chute 11. y

I preferably formthe blocks at the ends of the supporting plates 28, or at the side edges of the table, with flanges or projections 63', the flanges or projections on adjacent blocks forming a continuous protective and pinion 59, shown and also to permit cool These openings may wall extending lengthwise of the table, may be introduced in the lower part of the which walls on the upper run of the table chamber A, the gases of combustion passing cooperate with 10 'tudinal flanges 64 in the up the flue 17 which may beas shown, but upper portion of t e furnace to protect the would preferably be placed at the rear of the 5 metal portions of the table from the hot furnace. 7o blast, while the flanges on the lower run of When the construction described is to be the table 'coiiperate with walls 65 to protect employed only for rendering the material the lower metallic portions of the table porous previous to being calcined in a sepe from the blast, said walls 65 projecting verarate furnace or kiln, the temperature cre- 10 tically above the level of the track-rails 8. ated in the furnace by virtue of the burn- By this arrangement I am enabled to cming of the hot blast need only be in the neighploy a moving table, composed of parts borhood of 1300 to 1800 F., but, if the which must of necessity be metallic, in a construction is to be used both for renderfurnace where the temperatures range high ing the material porous and calcining, the

15 enough to melt or destroy ordinary metallic temperature attained should be from subparts, if such be subjected to direct effect of stantially 1800 F.- to 2500 F. the heat. When the liquid or plastic material with The parts being constructed and arranged the added chemicals is deposited upon the as above described, the process of treating surface of the highly heated table, the mois- 20 the phosphate and the operation of the appature will be evaporated very rapidly; that ratus in carrying out the process are as folis, be substantially flashed out of the matelows: rial, and a large portion of the chemicals The insoluble calcium phosphate, to be employed will be volatilized. This is due to converted into citrate solu 1e orm, is pulthe direct impingement of the blast, of the' 25 verified and reduced to a, plastic or liquid radiated heat from the furnace lining and state by mixture with water, the amount of blast, and the heat received from the table, water used being approximately 40 per cent. the moisture being, as stated, literally flashed of the calcium phosphate by weight. To out, leaving the material in thin, fragile, this mixture I add the alkali metal salt, porous sheets or flakes. In carrying out the 30 which may be sod'um sulfate or sodium carprocess with this apparatus it is highly debonate, the amount employed being about 15 sirable that the material be continuously r cent. b weight of the phosphate. The subjected to the heat without having addiendles's tab e having been heated in the furtional charges or supplies of the material sunace, the material in its liquid or plastic perimposed thereon, so that the pores of the 35 state is poured into the ho per 54, whence material will not be filled by additional it passes in a thin sheet t rough the slot charges, thereby closing the pores to the ac- 55. onto the highly heated upper surface of tion of the heat, and according to my inventhe table. As the table travels, the thin tion this result is efliciently attained, besheet of material is progressively laid on the cause, as the material is deposited on the 40 same and said material is sub ected to the table, it is subjected to the heat in a thin heat of the furnace. It will be understood layer, and then moved with the table through thatthe heating blast entering through the the chamber A, and then discharged therenozzle 13 passes in the direction opposite to from, before the blocks again reach the feed the direction of travel of the table and passes hopper.

45 lengthwise of the table, leaves the furnace What I claim and desire to secure by Letthrong the outlet 16 and, by way of the ters Patent of the United States is: flue 1 passes to the lower portion of the 1. The process of convertin insoluble furnace through the inlet 18, from which phosphate material to citrate so uble form,

' .lower portion it passes out through the stack which consists in addin thereto water and 5 19. 'By this arrangement the upper surface a suitable alkali metal sa t to provide a mix- 1 of the table is high y heated and the blocks, ture liquid or plastic in form, flowing the as they pass into the lower run of the table, mixture onto a highly heated surface tn form are maintained hot by the hot gases disa sheet or layer of substantially uniform charged into the lower part of the furnace, thickness whereby it is quickly deprived of 5 the result bein that the blocks are highly moisture and given the form of a porous heated when t ey reach the point where body or mass on said surface, and subjecting they receive the material from the feed hopthe porous material to a calcining temperaper. If it is not desired to heat the lower ture.

a, run of the table, the damper 21 in the flue 2. The process of converting insoluble 60 17 may be closed and the damper 15 in the phosphate material to citrate soluble form, stack 14 moved to open position to permit which consists in adding thereto water and the products to pa up the stack without a substance rendering the phosphate citrate passm to the lower ortion of the furnace soluble to produce a mixture liquid or plastic or, if it is not desi to have the material in form continuously flowing the mixture 65 in direct contact with the flame, the flame onto a highly heated surface to form a sheet or layer of substentially urriform thickness In testimony whereof I haw re' hereunto whereby it is quickly deprived of moisture sigped my name in the presenoe of two suband iven the form of a, porous body or mass sorlbmg witnesses.

on said suriaoe, subjecting the porous mate- ELLIS C. SOPER. 6 riel to a ealcmlng temperature and con- Witnesses:

tinuously removing the material from said O. P. DARWIN,

surface after ealcmation. J. H. McCnmu.

11 i; hmbj unified 11m. in Letters P m; No. 1,281,681, granted October 15, 1918, upon tho application of Ellis 0. Super, of Chattanooga, Tennessee; for an improvement in The Treatment of Phosphateo," errors appear in the printod specification correction as follows: P age 1,lines 76-77, for the words embodying my invention" road capable of carrying my invention into eject; page 3, lino 7, for the word shaft road Mafia; same page, line 8, for the word on read and; and that the said Letters Patent should be read with these corrections therein thot the some may conform 10 tho record of the case in 'tho Patont Office.

Signed ma mm this 10111 day of December, A. 1)., 1918.

F. W. H. CLAY, 11am WWW of Patents. 

